1. Field of the Invention
The present invention generally relates to a light-emitting device, in particular, to an electron emission light-emitting device and applications thereof.
2. Description of Related Art
Currently, mass-produced light source apparatus or display apparatus mainly employ two types of light-emitting structures, which are described as follows.                1. Gas-discharge light sources: the gas-discharge light sources are applicable to, for example, plasma panels or gas-discharge lamps, for ionizing the gas filled in a discharge chamber by the use of an electric field between a cathode and an anode, such that electrons impinge the gas by means of glow discharge to generate transition and emit ultraviolet (UV) lights. And, a fluorescent layer located in the same discharge chamber absorbs the UV lights to emit visible lights.        2. Field emission light source: the field emission light source are applicable to, for example, carbon nanotube field emission display, for providing an ultra high vacuum environment, and an electron emitter made of a carbon nanomaterial is fabricated on a cathode, so as to help the electrons to overcome the work function of the cathode to depart from the cathode by the use of the microstructure of high aspect ratio in the electron emitter. Moreover, a fluorescent layer is coated on an anode made of indium tin oxide (ITO), such that the electrons escape from the carbon nanotube of the cathode due to a high electric field between the cathode and the anode. Therefore, the electrons impinge the fluorescent layer on the anode in the vacuum environment, so as to emit visible lights.        
However, the above two types of light-emitting structures have disadvantages. For example, the attenuation occurs after the irradiation of the UV lights, so that specific requirements must be taken into account in selecting the material in the gas-discharge light source. Moreover, the gas-discharge light-emitting mechanism emits the visible lights through two processes, so that more energy is consumed, and if the plasma must be generated in the process, more electricity is consumed. On the other hand, the field emission light source requires a uniform electron emitter to be grown or coated on the cathode, but the mass production technique of this type of cathode structure is not mature, and the uniformity and a poor production yield of the electron emitter are still bottlenecks. Further, a distance between the cathode and the anode of the field emission light source must be accurately controlled, and the ultra high vacuum packaging is quite difficult and also increases the fabrication cost.